Generally, a white balance adjusting device is provided in a video display device such as a television receiver. In the video display device using a CRT (Cathode Ray Tube), gamma correction curves are separately set for an R-signal (red signal), a G-signal (green signal) and a B-signal (blue signal) for gamma correction.
When a user adjusts a white balance of the video display device, for example, the user displays an adjustment menu by OSD (On Screen Display) on a screen by an operation key on the front of the video display device. The user controls gains of R (red), G (green) and B (blue), respectively, in a user mode in the adjustment menu by the operation key to change the gamma correction curves set separately for the R-signal, the G-signal and the B-signal with the amounts of correction corresponding to the gains Thus, the white balance of the image on the entire screen is adjusted by controlling mutual balance among levels of the R-signal, the G-signal and the B-signal.
There is also a proposed method that a user adjusts a white balance by selecting any of color temperatures referred to as “9300K”, “6500K” and “5800K” in letters in an adjustment menu by the OSD (refer to Patent Document 1).
[Patent Document 1] JP 55-25207 A